644271311 has 2 divisors, whose sum is σ = 644271312. Its totient is φ = 644271310.

The previous prime is 644271259. The next prime is 644271359. The reversal of 644271311 is 113172446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644271311 is a prime.

It is equal to p_33510944 and since 644271311 and 33510944 have the same sum of digits, it is a Honaker prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644271371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322135655 + 322135656.

It is an arithmetic number, because the mean of its divisors is an integer number (322135656).

Almost surely, 2^644271311 is an apocalyptic number.

644271311 is a deficient number, since it is larger than the sum of its proper divisors (1).

644271311 is an equidigital number, since it uses as much as digits as its factorization.

644271311 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 29.

The square root of 644271311 is about 25382.5000935684. The cubic root of 644271311 is about 863.6867644358.

The spelling of 644271311 in words is "six hundred forty-four million, two hundred seventy-one thousand, three hundred eleven".